JP2843351B2 - Gas filter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention particularly relates to a gas filter for treating a gas such as an exhaust gas from an internal combustion engine such as an engine or a diesel engine and removing harmful components therefrom. It is about.

<Problems to be Solved with Conventional Technique> The filter is provided with a filter body having a plurality of inflow channels and outflow channels separated from each other by partition walls forming a reaction chamber.

In particular, when removing soot and other similar harmful substances from exhaust gas of a diesel engine, a soot filter made of a ceramic material is known. In such an application, it is installed on the downstream side.

The hot gas emanating from the engine flows into the inlet channels of the filter body, passes through the porous filter wall surrounding the inlet channels, and is exhausted through the respective outlet channels.

Because of the high temperature conditions, soot, or carbonaceous material, is turned into gaseous matter and ash in the filter walls, which are discharged from the exhaust duct together with the exhaust gas.

A particular problem with ceramic filters lies in their special porosity, which promotes soot separation while also limiting, especially the pore size distribution and spherical shape. However, the porosity cannot be changed significantly due to the special structural characteristics of the ceramic material.

Ceramic filters also have other disadvantages. They are very sensitive to rapid temperature changes, are locally heated by exhaust gases due to their low thermal conductivity, and are susceptible to shocks, blows and other impact stresses. That is, the outside of the filter body must be surrounded by a material that protects against heat and shock, typically stone wool, and this protection must be placed in the housing. For this reason, known soot filters take considerable space, but there is a problem that the space allowed in the engine room of an automobile is often limited.

Obviously, ceramic filters have recovery problems when they are coated with catalytically active metals such as platinum, rhodium, vanadium and palladium. To recover these metals from the ceramic body, very cumbersome methods have to be taken.
Also, while the useful life of such ceramic bodies is reduced due to stress, this problem is a significant cost factor that must be addressed during the manufacture and final sale of the ceramic body.

Exhaust gas catalysts are known which remove additional harmful substances such as carbon monoxide, hydrocarbons and nitrogen oxides from the exhaust gas by catalysis. For this, filters coated with platinum, rhodium, vanadium and other catalyzing substances are used. However, such filters based on ceramic materials are expensive and even sensitive to the operating environment.

The object of the present invention is without the above disadvantages, particularly robust,
Another object of the present invention is to provide a filter of the above-described type that can easily change the shape of the filter body.

<Means and Actions for Solving the Problems> According to one feature of the present invention, there is provided a filter formed by using a filter body made of a heat-resistant compression-solidified / molded / sintered material as a wall material. .

The filter body of the present invention made of a sintered part is relatively resistant to shocks such as temperature shock, blow or collision.
An even greater advantage over conventional filter bodies is that they can be configured in any desired shape. That is, it means that the filter can be optimized for the state of the space in which it is used. Thus, for example, it can be square, rectangular, elliptical, or any other desired shape.

A further advantage of the filter body according to the invention is that, due to its relatively high thermal conductivity and a large internal surface area, soot particles are well dispersed in the individual fibers and gasification is enhanced.

Due to the large surface area and high thermal conductivity of the filter due to the cross-linked partial sintering, the heat distribution in the filter becomes uniform, so the separated carbon burns almost uniformly over the entire area even at a relatively low temperature ( Oxidation) and the pressure fluctuations in the filter are considerably reduced.

Furthermore, in addition to the advantages mentioned above, the large surface area of the filter allows the catalysis or effect to be maximized, so that solid soot can be converted to gaseous products at lower temperatures than conventional ones.

Based on the above advantages, the efficiency of the filter according to the invention is particularly high.

In particular, the following effects can be obtained when compared with a conventional ceramic filter.

By stacking the metal fibers irregularly and then sintering their contact sites or surfaces, it is possible to obtain a very large surface area with a high thermal conductivity, ie with a good heat distribution.

Therefore, the soot filter can be heated very quickly and uniformly.

Thus, for example, soot transformation, that is, soot gasification, begins at about 250-300 ° C. At about 350-400 ° C, the alteration of soot proceeds by 50%, and at about 600-680 ° C, the alteration of soot is almost completed. Thus, the sharp increase in efficiency at low temperatures is surprising.

On the other hand, the soot deterioration of the conventional filter is 400 ° C.
Starting from the above, a transformation of soot of 50% is finally achieved at about 500-600 ° C. It is generally above 750 ° C. that the soot changes almost completely with prior art filters.

This increased efficiency is particularly beneficial for vehicles used for short-distance travel, i.e., with diesel engines, where the engine often operates in cold conditions, and in such use conditions common ceramics are used. Filters have almost no effect.

The filters of the present invention are simpler to manufacture and lower in cost because the components required to protect conventional sensitive ceramic structures, such as stone wool and intermediate mantle, can be eliminated.

It is only necessary that the material constituting the filter body has a sufficiently high melting point, that is, a heat-resistant material is used.

Also surprisingly, it has been found that the exhaust gas filter of the present invention has a high sound deadening ability.

For this reason, in a further embodiment of the present invention, at least a part of the filter is shaped like a muffler.

Since the filter body can be manufactured simply and practically and almost without problems, and can be made in various shapes while maintaining the effect of purifying exhaust gas, at least a part of the conventional muffler structure, for example, initial or A pre-muffler (initial or pre-muffler) can be substituted for this.

In this way, a further object of the filter according to the invention is achieved. When the filter body is formed in such a shape, a special muffler structure is not required, so that the cost can be significantly reduced as compared with the conventional method and apparatus.

Advantageously, the metal container can be sintered (bonded or compacted) into a compacted / compacted or sintered part. In this way, it is possible to form a small unit and a soot filter capable of withstanding high stress and load since they are homogeneous and integral.

The molded part contains heat-resistant alloy steel powder together with chromium and / or molybdenum, manganese, cobalt, nickel and the like as alloy components.

Thus, heat resistance and thermal stability of the filter body can be obtained.

Further, it is also possible to utilize the catalytic action of the filter for altering harmful components in the exhaust gas, for example, carbon monoxide, hydrocarbons, nitrogen oxides, and the like. This has the advantage that the application of the filter is expanded.

A catalytic substance is added to the filter of the present invention in order to controllably remove components other than soot that are undesirable, ie, harmful or toxic, to the environment. This can be achieved by coating the sintered part with platinum, rhodium, vanadium, palladium, etc., thereby also removing carbon monoxide, hydrocarbons and nitrogen oxides from the exhaust gas.

In a highly advantageous and inventive embodiment of the present invention, the filter body is formed by molding or compress-solidifying a metal wire or metal tip into a molded article and then sintering.

By manufacturing a sintered body made of a metal wire or a metal tip, a structure having a low density and a high material rigidity / strength can be obtained. This means that the sintered component thus formed has a high penetrating power, that is, a high penetrating power, and it is possible to widen the range of application to various applications by various effects.

The diameter or width of a metal wire piece or metal tip is 0.1
5 mm and a length of about 0.5-30 mm, preferably 1-3 mm and 2-10 mm, respectively. Also, one or several equally long metal wires may be provided in a mesh or similar crossed weave. As a result, the individual components can be joined together by a method such as electric welding to produce a structure having the characteristics of a sintered body. In this case, the relative resistance to permeability is considerably reduced.

According to another embodiment, the filter body is formed by combining several identically molded or compacted parts.

If the filter is formed by combining a plurality of identical molded parts, it can be combined in an articulated shape or a block shape according to individual requirements and required dimensions, thereby simplifying production and reducing costs. Can be achieved.

The compacted / compacted parts may be individually sintered and then assembled, or if formed integrally by sintering during molding to form a unitary filter body, a fairly hard and homogeneous filter unit is obtained.

Sintered filter bodies can be manufactured with a wide selection of channel shapes, which can be tailored to their conditions and requirements.

The components are formed in rows with channels that can be inflow channels or outflow channels according to their arrangement. However, the shape of the channel can be as desired.
Therefore, various shapes and sizes can be selected for the inflow channel and the outflow channel to which soot adheres. This means that the filter can be adjusted in an optimal state for the application.

In a preferred embodiment of the invention, each molded part consists of a single plate, with several channels formed in the longitudinal walls of the plate, separated from each other by cross pieces. The channel is open on one front side to form an inflow or outflow opening and the other front side is closed off by a transverse crosspiece.

In practice, only one type of component is required to achieve this shape, and each plate can be used both on the inflow and outflow sides by arranging the individual plates in a special arrangement or in a continuous arrangement. .

Of course, the shape of the filter body can be changed variously within the scope of the invention.

The desired shaping can be carried out without problems in a practical manner. For this purpose, it is also possible for the filter body to be constituted, for example, by one or a plurality of bent or spiral wound sintered metal bands or strips, with bent ribs, beads or bends arranged parallel to one another. The inflow and outflow channels are formed by the cross pieces.

In a further embodiment of the invention, several filter cartridges are provided next to each other and / or continuously when viewed in the flow direction, so that the exhaust gas flows from the outside to the inside or vice versa. I have to.

This embodiment has the advantage that the replacement or replacement of individual components required in the event of an operational loss due to breakage or clogging is further facilitated.

Instead of coating the sintered part with a catalytic material,
In a further preferred embodiment of the invention, a part, at least partly formed of or coated with a catalytic substance of the kind described above, is inserted into the filter body. It may be slid into one or several filter bodies or arranged upstream or downstream in the flow direction, taking into account the flow direction.

The material can be made, for example, of a metal wire extending inside the filter body like a sensor. They can be configured in a circular shape and, for example, fit into the filter body from the front end. If worn out or deteriorated, replace it as necessary at the time of regular inspection of the vehicle.

Alternatively, a catalyst material in the form of a wire mesh, a pin or a rod, or a base material coated with the catalyst material may be provided upstream or downstream of the filter body on the exhaust gas path. In this case, the hot exhaust gas scrapes off the catalytic material, which adheres to the soot layer of the filter body, where it catalyzes. In this way, it is possible to prevent deterioration of the catalytic action when the soot layer increases. Further, in this embodiment, since the inspector can easily check the consumption amount of the catalyst substance and replace it as necessary, the replacement is simplified.

In a preferred embodiment of the invention, the filter body is arranged in combination with a conventional soot filter for exhaust gas and / or a filter. Thus, for example, in special cases, the filter body according to the present invention can be combined with a ceramic filter in a sandwich manner or a desired combination.

<Examples> Next, the present invention will be described in detail based on examples shown in the accompanying drawings.

The filter according to the embodiment shown in FIGS. 1 to 3 is provided with a steel plate container 1 which is a jacket of a filter body 2 composed of several plate parts 3 which are form or shaped parts. Have been.

The molded part 3 is sintered to become a sintered part. A plurality of channels 4, 5 are formed in the longitudinal wall of each molded part 3, i.e., each plate, which may be an inlet channel 4 or an outlet channel 5 depending on the arrangement. The channel extends parallel to the longitudinal edge of the plate 3 and its depth is equal to about half the width of the plate 3. Therefore, the width of the cloth piece 6 is almost the same as that of the channels 4 and 5.

The filter can be used to remove harmful components from exhaust gas, particularly exhaust gas from internal combustion engines such as combustion engines and diesel engines. Inflow channel 4
Is separated from the outlet channel 5 by a partition 10 forming a reaction chamber. The filter body 2 can include a heat-resistant compression-solidified / molded / sintered material.

The plate 3 can include a heat-resistant alloy component such as chromium, molybdenum, nickel, and manganese. Similarly, the filter can also include an alloy component that includes at least a catalytic component such as chromium, platinum, rhodium, vanadium, palladium, molybdenum, nickel, copper, or manganese.

As shown in FIGS. 2 and 3, the channels 4 and 5 have one end face 7 open while the other end face 8 is closed by a cross piece 9.

The gas flows in the filter according to the invention in the direction of the arrow in FIG. 2, the open sides of the channels 4 and 5 face the longitudinal wall 10, i.e. the rear wall facing the wall forming the channels 4 and 5, and are arranged adjacently. Plate 3 closes the channel. Thus, in this way, a closed channel system is formed in which the end facing the inflow side is closed by the cross piece 9.

As can be seen from the arrows in FIG.
Flows into the inflow channel 4, but the exhaust gas permeates through the porous filter wall of the plate 3 because the lower end of the inflow channel 4 is closed by the cross piece 9.

A chemical reaction, such as soot, occurs in the filter wall 11, that is, it turns into gas and ash. From the filter wall 11, purified exhaust gas flows into the outlet channel 5. As shown in FIG. 2, the outlet channel 5 is provided with an outlet passage 12 at the lower end, and the inlet side is closed by a cross piece 9.

A desired number of plates 3 can be arranged in parallel.
The number of plates corresponds to the number of channels 4 and 5 juxtaposed and thus to the length of the plate 3.

Furthermore, as can be seen from FIGS. 2 and 3, the plate parts 3 are all substantially identical in shape, so that the relative arrangement of the individual plates forms the inflow channel 4 and the outflow channel 5.

Plates that are joined together during sintering, ie, sintered parts
Are indicated by dotted lines. FIG. 3 shows the two parts before sintering.

As can be seen from FIG.
Are rotated by 180 ° with respect to each other, that is, are arranged in an inverted state with respect to each other. The rear face or wall 10 of the component 3 is thus located at the position of the adjacent crosspiece 9 and / or the front end of each crosspiece.

In order to manufacture the filter according to the present invention, the same plate molded part 3 is formed by compression and solidification into a desired shape by a compression molding machine. Next, a desired number of them are juxtaposed in a desired posture and then sintered.

 Thereby, the integral filter body 2 is formed.

Thereafter or at the same time, the container 1 made of a steel plate may be sintered on each of the outer plates 3 so that stable and intimate bonding can be performed. In order to perform this as needed, it is only necessary to use a sintered powder having a low melting point as needed, and thereby the molded part and the steel sheet container 1 can be joined.

The component 3 can be formed of a noble alloy steel powder that can be sintered in the same manner as the metal powder, or a corresponding heat-resistant noble metal wire or chip.

FIG. 4 shows another embodiment of the exhaust gas filter according to the present invention. In this embodiment, a plurality of individual hollow cylindrical filter cartridges 13 are arranged side by side and / or continuous in the flow direction, preferably arranged in a circular or several rows. The cartridge 13 is open at one end, that is, at the inflow side, and is closed at the other end. These can be replaced together and attached to the base plate 14 as needed. A jacket-like wall 15 surrounds the outside of the filter.

As is apparent from the drawing, the exhaust gas to be purified enters the cylindrical cartridge 13 from the open end, passes through the surrounding wall, and flows out as the purified gas from the opposite end.

When one wall surface, preferably the inner peripheral wall of the filter cartridge 13 is coated with a catalytic substance, it is possible to further modify other harmful exhaust gas besides burning soot.
The phantom line 16 in FIG. 4 shows this coating. Of course, the coating can be applied at other locations.

FIGS. 5 and 6 show still another embodiment, and are schematic views showing the principle of operation. Cross pieces 24 are arranged at equal intervals on a base body 23 made of a sintered material.

Next, when the strip with the crosspiece 24 is spirally wound, the formed inflow and outflow channels are each closed at one end. If the cloth piece 24 is also made of a sintered material, all parts can be sintered in their final state and shape, respectively.

FIG. 7 shows the shape of the filter body 2 into which some catalytic substances are inserted, and mainly explains the principle.
In the gas inflow conduit 19 following the filter body 2, there are provided several pins 20 made of a catalytic substance or a material coated with a catalytic substance.

The hot gas scrapes off the catalytic material of the pins 20 and the scraped off material adheres to the walls of the filter body 2 where it exerts its action. Further, for the same purpose, a catalytically active substance or a substance coated with such a substance may be provided in the gas inflow conduit 19 instead of the pin 20 or in addition to the pin 20 to form a mesh or a fabric structure 21. .

Alternatively, a wire-shaped metal sensor 22, which is entirely or partially composed of a catalytic substance or coated with such a substance, may be inserted directly into the filter body. They can be inserted axially from one end face, preferably from the inflow end face. If necessary, several wire sensors 22 can be arranged in a circular shape.

In this way, the wire sensor 22 can be easily replaced when it deteriorates or wears out.

The type and shape of the wire sensor 22 can be as desired and are tailored to the respective application. For simplicity, FIG.
Here all of the above solutions are shown with catalyst inserts. Of course, the inserts can be made individually,
It may be deformed.

If one or several hollow cylindrical filter cartridges are used instead of a plate-like filter as shown in FIGS. 1-3, they will be shaped to mute or attenuate the sound during operation. Can be. In this case, it is sufficient to secure a sufficiently long path and a sufficient residence time for altering or removing harmful components of the exhaust gas, so that the muffler and the exhaust gas filter are inevitably used. Will be.

The filter body of the present invention can be used in combination with other conventional exhaust gas catalysts, if necessary, and there are various ways.

For example, as shown in FIG.
Are arranged in series in the front-rear direction. For example, the first filter 17 is mainly for burning soot, and the second filter 18 is a ceramic filter. Any arrangement method may be used. Of course, filters made of various materials, such as the sintered part according to the invention and the ceramic plate, are shaped so that they can be accommodated in the same housing.

In this case, for example, to connect each plate or sintered part to a ceramic plate or a metal plate, a metal cam portion is inserted into a hole in the ceramic plate and connected to an adjacent metal plate. Next, the entire sandwich structure is sintered or joined.

Similarly, tubes made of concentrically arranged metal fibers or ceramic material may be sintered and closely bonded. At this time,
The ceramic body may be firmly joined so as not to move in the metal plate or the frame and not be affected by the vibration of the vehicle.

The fixation of the filter to the housing can be done successfully with metal fibers or sintered plates.

Of course, the filter of the present invention is not only suitable for removing or altering gas generated in a combustion type engine. It can likewise be used for the removal of gases generated in the desired type of heating and / or combustion equipment in which harmful gases are generated. For example, when burning wood, coal, oil, and the like.

The catalytic material was coated with platinum, rhodium, vanadium, palladium or other catalytically active material,
Or a substance combined with such a substance.

The embodiments described above are mainly for explanation, and do not limit the present invention. All modifications that do not depart from the spirit, concept and features of the invention are deemed to be within the scope of the appended claims.

[Brief description of the drawings]

FIG. 1 is a plan view of a partial cross section showing an upper surface of a filter according to an embodiment of the present invention, FIG. 2 is a cross sectional view taken along line II-II in FIG. 1, and FIG. FIG. 4 is a cross-sectional view of two separate molded parts according to the present invention, FIG. 4 is a partially cutaway side view of a filter body of another embodiment according to the present invention, and FIG. 5 is still another embodiment according to the present invention. Side view showing the base material of the filter body of FIG.
FIG. 7 is a side view schematically showing a spirally wound body based on the filter body of FIG. 5, FIG. 7 is a side view of a filter body used as a catalyst, and FIG. It is a side view which shows. DESCRIPTION OF SYMBOLS 1 ... Container 2 ... Filter body 3 ... Molded part 4 ... Outflow channel 5 ... Inflow channel 9, 24 ... Cross piece 10 ... Wall surface 11 ... Filter wall 13 ... Cartridge 20 ... Pin 22 ... … Metal sensor

Claims (18)

(57) [Claims] 1. A gas filter for removing harmful substances from a gas stream, particularly from exhaust gas of an internal combustion engine such as an engine or a diesel engine. A gas filter, characterized in that each of the plurality of inflow and outflow channels separated from one another by a material comprises a plate provided with at least one cross piece. 2. The filter according to claim 1, wherein each of the wall members of the filter body made of a heat-resistant substance is separated from each other by a cross piece, and an inflow and an outflow opening are formed at the right end of each drum of the filter body. A gas filter as described. 3. The gas filter according to claim 1, wherein the wall material of the filter body made of a heat-resistant substance is obtained by compression and solidification. 4. The gas filter according to claim 1, wherein the wall material of the filter body made of a heat-resistant substance is obtained by sintering. 5. The wall material of a filter body made of a heat-resistant substance,
The gas filter according to claim 1, wherein the gas filter contains at least one of chromium, molybdenum, nickel, and manganese. 6. A wall material of a filter body made of a heat-resistant substance,
The gas filter according to claim 1 or 2, further comprising at least one catalyst component of chromium, platinum, rhodium, vanadium, palladium, molybdenum, nickel, copper, and manganese. 7. The filter according to claim 1, wherein the wall material of the filter body made of a heat-resistant substance is obtained by compression-solidifying and / or sintering a metal wire or a metal tip.
2. A gas filter according to item 1. 8. The gas filter according to claim 1, wherein a wall member of the filter body made of a heat-resistant substance and a cross piece are integrally formed. 9. The gas filter according to claim 1, wherein the gas filter can function at least partially as a muffler. 10. A motor for use in a motor.
2. A gas filter according to item 1. 11. A vehicle for use in an automobile.
2. A gas filter according to item 1. 12. The gas filter according to claim 1, wherein the gas filter is used in combination with a ceramic material. 13. The gas filter according to claim 12, wherein the ceramic material is provided with a coating of a substance that acts catalytically. 14. The method according to claim 1, wherein the substance contained in the coating of the substance acting as a catalyst contains at least one selected from the group consisting of platinum, rhodium, vanadium and palladium. Gas filter. 15. The gas filter according to claim 1, further comprising at least one sensor-type member. 16. The method according to claim 1, wherein the material is made of at least one of platinum, rhodium, vanadium, and palladium.
The sensor according to 5). 17. The sensor according to claim 16, wherein the sensor is coated with at least one of platinum, rhodium, vanadium, and palladium. 18. The gas filter according to claim 1, wherein a band having a spiral arrangement is provided.